1,253 research outputs found

    Influence of Timber Harvesting Operations and Streamside Management Zone Effectiveness on Sediment Delivery to Headwater Streams in Appalachia

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    Disturbances created by timber harvesting equipment and associated haul roads and skid trails can create overland sediment flows (sediment paths), especially in steeply sloping terrain, leading to stream sedimentation. This study investigated the effect of variables associated with GPS tracked harvest equipment movement, skid trail development and retirement, topography, and streamside management zone (SMZ) width and tree retention on sediment delivery to streams. While the intensity of harvest equipment traffic was not correlated with sediment path development, the presence and location of skid trails were. All of the sediment paths were found to originate at water control structures, influenced by microtopographic features, on the skid trails directly adjacent to SMZs. Mesic slopes were associated with increased sediment path development across all SMZ configurations. Two factors, the accumulation of coarse logging debris in the SMZ and the increased distance of skid trails to streams, were both correlated with decreased sediment path development. The study provides insight into how these variables interact and can be used to develop site-specific guidelines for SMZs in steeply sloping terrain that could improve their efficiency and effectiveness

    Assessment of Streamside Management Zones for Conserving Benthic Macroinvertebrate Communities Following Timber Harvest in Eastern Kentucky Headwater Catchments

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    Headwater streams generally comprise the majority of stream area in a watershed and can have a strong influence on downstream food webs. Our objective was to determine the effect of altering streamside management zone (SMZ) configurations on headwater aquatic insect communities. Timber harvests were implemented within six watersheds in eastern Kentucky. The SMZ configurations varied in width, canopy retention and best management practice (BMP) utilization at the watershed scale. Benthic macroinvertebrate samples collected one year before and four years after harvest indicated few differences among treatments, although post-treatment abundance was elevated in some of the treatment streams relative to the unharvested controls. Jaccard index values were similar across SMZ treatments after logging, indicating strong community overlap. These findings suggest that stream invertebrate communities did respond to the timber harvest, though not negatively. Results also suggest that SMZ criteria for aquatic habitats in steeply sloping topography, including at least 50 percent canopy retention and widths of at least 16.8 m, appear to be adequate for protecting benthic macroinvertebrate communities from logging impacts

    Development and Validation of a Clinical Scoring System to Differentiate Patients with Inflammatory Bowel Disease and Diarrhea-Predominant Irritable Bowel Disease

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    Background: There is no validated scoring system for differentiating inflammatory bowel disease (IBD) from irritable bowel syndrome (IBS). Studies variably report clinical measures such as radiology, endoscopy, inflammatory markers, and symptoms to separate IBS from IBD. Our study seeks to create a system to IBD patients from IBS. The “REBISS” score incorporates various clinical criteria used commonly for diagnosis. We also studied a second system called “REBISS-PCP” focusing on a subset of criteria that are available to PCPs when faced with this challenge. Methods: This study was approved by the UMass IRB. Two cohorts were identified: 24 IBD patients (Group1) and 24 IBS patients (Group2). Subjects in Group1 were patients with Crohn’s or ulcerative colitis. Subjects in Group2 were identified as having IBS based on ROME III criteria. Retrospective analysis was performed and a score was calculated. One point is assigned for having: radiological findings consistent with IBD, endoscopic findings of inflammation or ulceration, biopsy findings consistent with IBD, elevated inflammatory markers, weight loss, hematochezia, extra-intestinal signs/symptoms, palpable mass on exam, and perianal disease. The maximum score is 10 points. For the REBISS-PCP score, the same clinical criteria were studied with the exclusion of endoscopic and biopsy findings. Maximum score for that system is 8 points. A likelihood ratio chi-square test was performed for both cohorts and scoring systems. Results: The REBISS scoring system showed a significant differentiation of the two cohorts in regards to scoring distribution (chi-square value = 59.8; p\u3c0.0001). The REBISS-PCP scoring system also found a significant differentiation of the two cohorts (chi-square value = 35.7;p\u3c 0.0001). Discussion: The REBISS scoring system could be used to standardize IBD and IBSd populations in an academic research setting, while both the REBISS and REBISS-PCP scoring system could be used as a screening tool in clinical practice

    Restoration of a Severely Impacted Riparian Wetland System - The Pen Branch Project

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    The Savannah River Swamp is a 3020 ha forested wetland on the floodplain of the Savannah River and is located on the Department of Energy’s Savannah River Site (SRS) near Aiken, SC (Fig. 1). Historically the swamp consisted ofapproximately 50% baldcypress-water tupelo stands, 40% mixed bottomland hardwood stands, and 10% shrub, marsh, and open water. Tributeries of the river were typical of Southeastern bottomland hardwood forests. The hydrology was controlled by flow from four creeks that drain into the swamp and by flooding of the Savannah River. Upstream dams on the Savannah River have caused some alteration of the water levels and timing of flooding within the floodplain(Schneider et al., 1989)

    Clinical Outcomes of Gamma Knife Radiosurgery in the Treatment of Patients with Trigeminal Neuralgia

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    Since its introduction by Leksell, Gamma Knife radiosurgery (GKRS) has become increasingly popular as a management approach for patients diagnosed with trigeminal neuralgia (TN). For this reason, we performed a modern review of the literature analyzing the efficacy of GKRS in the treatment of patients who suffer from TN. For patients with medically refractory forms of the condition, GKRS has proven to be an effective initial and repeat treatment option. Cumulative research suggests that patients treated a single time with GKRS exhibit similar levels of facial pain control when compared to patients treated multiple times with GKRS. However, patients treated on multiple occasions with GKRS are more likely to experience facial numbness and other facial sensory changes when compared to patients treated once with GKRS. Although numerous articles have reported MVD to be superior to GKRS in achieving facial pain relief, the findings of these comparison studies are weakened by the vast differences in patient age and comorbidities between the two studied groups and cannot be considered conclusive. Questions remain regarding optimal GKRS dosing and targeting strategies, which warrants further investigation into this controversial matter

    The Quasar / Galaxy Pair PKS 1327-206 / ESO 1327-2041: Absorption Associated with a Recent Galaxy Merger

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    We present HST/WFPC2 broadband and ground-based Halpha images, H I 21-cm emission maps, and low-resolution optical spectra of the nearby galaxy ESO 1327-2041, which is located 38 arcsec (14 kpc in projection) west of the quasar PKS 1327-206. Our HST images reveal that ESO 1327-2041 has a complex optical morphology, including an extended spiral arm that was previously classified as a polar ring. Our optical spectra show Halpha emission from several H II regions in this arm located ~5 arcsec from the quasar position (~2 kpc in projection) and our ground-based Halpha images reveal the presence of several additional H II regions in an inclined disk near the galaxy's center. Absorption associated with ESO 1327-2041 is found in H I 21-cm, optical, and near-UV spectra of PKS 1327-206. We find two absorption components at cz = 5255 and 5510 km/s in the H I 21-cm absorption spectrum, which match the velocities of previously discovered metal-line components. We attribute the 5510 km/s absorber to disk gas in the extended spiral arm and the 5255 km/s absorber to high-velocity gas that has been tidally stripped from the disk of ESO 1327-2041. The complexity of the galaxy/absorber relationships for these very nearby H I 21-cm absorbers suggests that the standard view of high redshift damped Lyman-alpha absorbers is oversimplified in many cases.Comment: Replaced with accepted version; 16 page

    Evidence to support IL-13 as a risk locus for psoriatic arthritis but not psoriasis vulgaris

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    Objective: There is great interest in the identification of genetic factors that differentiate psoriatic arthritis (PsA) from psoriasis vulgaris (PsV), as such discoveries could lead to the identification of distinct underlying aetiological pathways. Recent studies identified single nucleotide polymorphisms (SNPs) in the interleukin 13 (IL-13) gene region as risk factors for PsV. Further investigations in one of these studies found the effect to be primarily restricted to PsA, thus suggesting the discovery of a specific genetic risk factor for PsA. Given this intriguing evidence, association to this gene was investigated in large collections of PsA and PsV patients and healthy controls. Methods: Two SNPs (rs20541 and rs1800925) mapping to the IL-13 gene were genotyped in 1057 PsA and 778 type I PsV patients using the Sequenom genotyping platform. Genotype frequencies were compared to those of 5575 healthy controls. Additional analyses were performed in phenotypic subgroups of PsA (type I or II PsV and in those seronegative for rheumatoid factor). Results: Both SNPs were found to be highly associated with susceptibility to PsA (rs1800925 ptrend = 6.1×10−5 OR 1.33, rs20541 ptrend = 8.0×10−4 OR 1.27), but neither SNP was significantly associated with susceptibility to PsV. Conclusions: This study confirms that the effect of IL-13 risk locus is specific for PsA, thus highlighting a key biological pathway that differentiates PsA from PsV. The identification of markers that differentiate the two diseases raises the possibility in future of allowing screening of PsV patients to identify those at risk of developing PsA
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